<font size=3 face="Arial">Regarding the permissions on the file I assume
you are not using ACLs, correct? If you are then you would need to
check what the ACL allows.</font><br><br><font size=3 face="Arial">Is your metadata on separate NSDs? Having
metadata on separate NSDs, and preferably fast NSDs, would certainly help
your mmbackup scanning.</font><br><br><font size=3 face="Arial">Have you looked at the information from netstat
or similar network tools to see how your network is performing? Faster
networks generally require a bit of OS tuning and some GPFS tuning to optimize
their performance.</font><br><br><br><br><font size=2 face="sans-serif">Regards, The Spectrum Scale (GPFS) team<br><br>------------------------------------------------------------------------------------------------------------------<br>If you feel that your question can benefit other users of Spectrum
Scale (GPFS), then please post it to the public IBM developerWroks Forum
at </font><a href="https://www.ibm.com/developerworks/community/forums/html/forum?id=11111111-0000-0000-0000-000000000479"><font size=2 face="sans-serif">https://www.ibm.com/developerworks/community/forums/html/forum?id=11111111-0000-0000-0000-000000000479</font></a><font size=2 face="sans-serif">.
<br><br>If your query concerns a potential software error in Spectrum Scale (GPFS)
and you have an IBM software maintenance contract please contact 1-800-237-5511
in the United States or your local IBM Service Center in other countries.
<br><br>The forum is informally monitored as time permits and should not be used
for priority messages to the Spectrum Scale (GPFS) team.</font><br><br><br><br><font size=1 color=#5f5f5f face="sans-serif">From:
</font><font size=1 face="sans-serif">Peter Childs <p.childs@qmul.ac.uk></font><br><font size=1 color=#5f5f5f face="sans-serif">To:
</font><font size=1 face="sans-serif">gpfsug main discussion
list <gpfsug-discuss@spectrumscale.org></font><br><font size=1 color=#5f5f5f face="sans-serif">Date:
</font><font size=1 face="sans-serif">07/10/2018 05:23 PM</font><br><font size=1 color=#5f5f5f face="sans-serif">Subject:
</font><font size=1 face="sans-serif">Re: [gpfsug-discuss]
Same file opened by many nodes / processes</font><br><font size=1 color=#5f5f5f face="sans-serif">Sent by:
</font><font size=1 face="sans-serif">gpfsug-discuss-bounces@spectrumscale.org</font><br><hr noshade><br><br><br><font size=3>Oh the cluster is 296 nodes currently with a set size
of 300 (mmcrfs -n 300)<br><br>We're currently looking to upgrade the 1G connected nodes to 10G within
the next few months.<br><br><br><br>Peter Childs<br>Research Storage<br>ITS Research and Teaching Support<br>Queen Mary, University of London<br><br><br>---- Peter Childs wrote ----<br></font><br><font size=3>The reason I think the metanode is moving around is I'd
done a limited amount of trying to track it down using "mmfsadm saferdump
file" and it moved before I'd tracked down the correct metanode. But
I might have been chasing ghosts, so it may be operating normally and nothing
to worry about.<br><br>The user reading the file only has read access to it from the file permissions,
<br><br>Mmbackup has only slowed down while this job has been running. As I say
the scan for what to backup usally takes </font><a href="tel:40-60"><font size=3 color=blue><u>40-60</u></font></a><font size=3>minutes, but is currently taking 3-4 hours with these jobs running. I've
seen it take 3 days when our storage went bad (slow and failing disks)
but that is usally a sign of a bad disk and pulling the disk and rebuilding
the RAID "fixed" that straight away. I cant see anything like
that currently however.<br><br>It might be that its network congestion were suffering from and nothing
to do with token management but as the mmpmon bytes read data is running
very high with this job and the load is spread over 50+ nodes it's difficult
to see one culprit. It's a mixed speed ethernet network mainly 10GB connected
although the nodes in question are legacy with only 1GB connections (and
40GB to the back of the storage.<br><br>We're currently running </font><a href="tel:4.2.3-8"><font size=3 color=blue><u>4.2.3-8</u></font></a><font size=3><br><br>Peter Childs<br>Research Storage<br>ITS Research and Teaching Support<br>Queen Mary, University of London<br><br>---- IBM Spectrum Scale wrote ----<br></font><br><font size=3 face="Arial">What is in the dump that indicates the metanode
is moving around? Could you please provide an example of what you
are seeing?</font><font size=3><br></font><font size=3 face="Arial"><br>You noted that the access is all read only, is the file opened for read
only or for read and write?</font><font size=3><br></font><font size=3 face="Arial"><br>What makes you state that this particular file is interfering with the
scan done by mmbackup? Reading a file, no matter how large should
significantly impact a policy scan.</font><font size=3><br></font><font size=3 face="Arial"><br>What version of Spectrum Scale are you running and how large is your cluster?</font><font size=3><br></font><font size=2 face="sans-serif"><br>Regards, The Spectrum Scale (GPFS) team<br><br>------------------------------------------------------------------------------------------------------------------<br>If you feel that your question can benefit other users of Spectrum
Scale (GPFS), then please post it to the public IBM developerWroks Forum
at </font><a href="https://www.ibm.com/developerworks/community/forums/html/forum?id=11111111-0000-0000-0000-000000000479"><font size=2 color=blue face="sans-serif"><u>https://www.ibm.com/developerworks/community/forums/html/forum?id=11111111-0000-0000-0000-000000000479</u></font></a><font size=2 face="sans-serif">.
<br><br>If your query concerns a potential software error in Spectrum Scale (GPFS)
and you have an IBM software maintenance contract please contact 1-800-237-5511
in the United States or your local IBM Service Center in other countries.
<br><br>The forum is informally monitored as time permits and should not be used
for priority messages to the Spectrum Scale (GPFS) team.</font><font size=3><br><br><br></font><font size=1 color=#5f5f5f face="sans-serif"><br>From: </font><font size=1 face="sans-serif">Peter
Childs <p.childs@qmul.ac.uk></font><font size=1 color=#5f5f5f face="sans-serif"><br>To: </font><font size=1 face="sans-serif">"gpfsug-discuss@spectrumscale.org"
<gpfsug-discuss@spectrumscale.org></font><font size=1 color=#5f5f5f face="sans-serif"><br>Date: </font><font size=1 face="sans-serif">07/10/2018
10:51 AM</font><font size=1 color=#5f5f5f face="sans-serif"><br>Subject: </font><font size=1 face="sans-serif">[gpfsug-discuss]
Same file opened by many nodes / processes</font><font size=1 color=#5f5f5f face="sans-serif"><br>Sent by: </font><font size=1 face="sans-serif">gpfsug-discuss-bounces@spectrumscale.org</font><font size=3><br></font><hr noshade><font size=3><br><br></font><tt><font size=2><br>We have an situation where the same file is being read by around 5000<br>"jobs" this is an array job in uge with a tc set, so the file
in<br>question is being opened by about 100 processes/jobs at the same time.<br><br>Its a ~200GB file so copying the file locally first is not an easy<br>answer, and these jobs are causing issues with mmbackup scanning the<br>file system, in that the scan is taking 3 hours instead of the normal<br>40-60 minutes.<br><br>This is read only access to the file, I don't know the specifics about<br>the job.<br><br>It looks like the metanode is moving around a fair amount (given what I<br>can see from mmfsadm saferdump file)<br><br>I'm wondering if we there is anything we can do to improve things or<br>that can be tuned within GPFS, I'm don't think we have an issue with<br>token management, but would increasing maxFileToCache on our token<br>manager node help say?<br><br>Is there anything else I should look at, to try and attempt to allow<br>GPFS to share this file better.<br><br>Thanks in advance<br><br>Peter Childs<br><br>-- <br>Peter Childs<br>ITS Research Storage<br>Queen Mary, University of London<br>_______________________________________________<br>gpfsug-discuss mailing list<br>gpfsug-discuss at spectrumscale.org</font></tt><font size=3 color=blue><u><br></u></font><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss"><tt><font size=2 color=blue><u>http://gpfsug.org/mailman/listinfo/gpfsug-discuss</u></font></tt></a><tt><font size=2><br></font></tt><font size=3><br><br><br></font><tt><font size=2>_______________________________________________<br>gpfsug-discuss mailing list<br>gpfsug-discuss at spectrumscale.org<br></font></tt><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss"><tt><font size=2>http://gpfsug.org/mailman/listinfo/gpfsug-discuss</font></tt></a><tt><font size=2><br></font></tt><br><br><BR>